The present invention generally relates to a transport system for integrated sampling devices and more specifically, but not exclusively, concerns a system in which a sterility cap is automatically removed from a lancet-sampler and a technique for manufacturing the same.
The acquisition and testing of bodily fluids is useful for many purposes and continues to grow in importance for use in medical diagnosis and treatment, such as for diabetes, and in other diverse applications. In the medical field, it is desirable for lay operators to perform tests routinely, quickly, and reproducibly outside of a laboratory setting, with rapid results and a readout of the resulting test information. Testing can be performed on various bodily fluids and, for certain applications, is particularly related to the testing of blood and/or interstitial fluid. Performing home-based testing can be difficult for many patients, especially for patients with limited hand dexterity, such as the elderly or diabetics. For example, diabetics can sometimes experience numbness or tingling in their extremities, such as their hands, which can make self-testing difficult because they are unable to accurately position a test strip to collect the blood sample. In addition, wounds for diabetics tend to heal more slowly, and as a result, there is a desire to make incisions less invasive.
Recently, lancet integrated test strips have been developed in which a test strip is integrated with a lancet or other piercing means so as to form a single disposable unit. While these integrated units have somewhat simplified the collection and testing of fluid samples, there are still a number of issues that need to be resolved before a commercial unit can be implemented. One issue concerns maintaining the sterility of the lancet so as to minimize the risk of infection. In practice, conventional plastic or syringe-type caps that are used to maintain the sterility of typical lancets cannot be incorporated with lancet integrated test strips for several reasons. With typical syringe-type caps, the cap encapsulates the lancet, and the cap is removed by pulling or twisting the cap off the lancet. As noted before, diabetics as well as the elderly can experience hand dexterity problems. Consequently, the manual removal of the cap from the lancet without destroying or damaging the integrated device can be difficult or even practically impossible. As of yet, a commercially practical system for automatically removing the cap has not been developed.
Integrated systems have been proposed that utilized closed needles that are manufactured through conventional needle drawing techniques. However, these conventional drawing techniques for needles can be rather expensive. Other systems have been proposed in which closed needles are manufactured using a semiconductor manufacturing process in which layers of semiconductor material are layered to form a closed needle. However, manufacturing a closed needle in such a way can be expensive and is not well suited for high volume production. Still yet other integrated disposables have been proposed that utilize a modified version of a conventional lancet for lancing the skin.
There is a trend to make lancets and needles smaller or thinner so as to make less traumatic or less invasive incisions, which in turn makes self-monitoring less painful as well as promotes healing of the incision. However, due to their thinner nature, lancets are more prone to bending or are susceptible to other damage, especially when protective caps are removed. Further, the pulling or twisting action during cap removal can damage the test strip, like the delicate electrodes in an electrochemical type test strip, or can even result in the lancet being separated from the test strip.
Other difficulties arise when a thinner lancet is used in integrated disposables in order to reduce pain. Some integrated disposable designs have an open capillary channel or groove formed in the lancet that is used to draw via capillary action body fluid from the incision to the test area or chamber. These open capillary groove integrated disposables experience a number of difficulties in drawing fluid via capillary action when the lancet is thin. As should be already appreciated, capillary action occurs when the adhesion of a liquid, such as body fluid, to the walls of the capillary channel is stronger than the cohesive forces between the liquid molecules. Adhesion of the liquid to the walls of the capillary channel causes the edge of the liquid to move upwards in the channel, and the surface tension acts to hold the surface of the liquid intact, so instead of just the edges moving upward, the whole liquid surface is dragged upward in the channel. However, with the open capillary groove designs, one of the walls of the capillary channel is eliminated, thereby reducing the overall contact area between the walls of the capillary channel and the surface of the body fluid. This reduction in contact area between the capillary channel and the body fluid reduces the capillary force applied to the fluid. To compensate, open capillary groove integrated disposables typically require that the capillary groove is deep so that the opposing sidewalls of the groove provide sufficient contact area with the meniscus to draw the body fluid. However, when the thickness of the lancet is reduced in order to reduce pain associated with lancing, the groove becomes too shallow to draw the body fluid via capillary action.
Integrated disposable designs have been proposed in which the entire unit is sealed within a protective packet. However, these designs require the entire disposable unit to be sterilized at the same time, which results in a whole host of difficulties. Unfortunately, sterilization techniques for lancets, such as radiation, adversely affect the chemistry of the test strip. Hence, if left uncompensated, the accuracy of the test strip can be significantly hampered. To compensate for the changes that occur during sterilization, samples from sterilized lots are taken so that an adjustment or calibration value can be calculated for the lot. Moreover, certain desirable sterilization techniques for lancets are impractical when the lancet and test strip are combined together because these techniques tend to damage or even destroy components on the test strip. In addition, undesirable cross contamination can occur between the lancet and the test strip when sealed in the same protective packet. For instance, components of the test strip, such as chemicals, biological components, adhesives, and the like, can migrate within the packet onto the lancet, thereby possibly compromising the sterility of the lancet.
Thus, needs remain for further contributions in this area of technology.